1. Field of the Invention
The invention relates to an implantable medical device such as an anastomosis device and a deployment system for implanting the device. In a preferred embodiment, the device can be used for forming a sutureless connection between a bypass graft and a blood vessel.
2. Brief Description of the Related Art
Vascular anastomosis is a procedure by which two blood vessels within a patient are surgically joined together. Vascular anastomosis is performed during treatment of a variety of conditions including coronary artery disease, diseases of the great and peripheral vessels, organ transplantation, and trauma. In coronary artery disease (CAD) an occlusion or stenosis in a coronary artery interferes with blood flow to the heart muscle. Treatment of CAD involves the grafting of a vessel in the form of a prosthesis or harvested artery or vein to reroute blood flow around the occlusion and restore adequate blood flow to the heart muscle. This treatment is known as coronary artery bypass grafting (CABG).
In the conventional CABG, a large incision is made in the chest and the sternum is sawed in half to allow access to the heart. In addition, a heart lung machine is used to circulate the patient""s blood so that the heart can be stopped and the anastomosis can be performed. During this procedure, the aorta is clamped which can lead to trauma of the aortic tissue and/or dislodge plaque emboli, both of which increase the likelihood of neurological complications. In order to minimize the trauma to the patient induced by conventional CABG, less invasive techniques have been developed in which the surgery is performed through small incisions in the patients chest with the aid of visualizing scopes. Less invasive CABG can be performed on a beating or stopped heart and thus may avoid the need for cardiopulmonary bypass.
In both conventional and less invasive CABG procedures, the surgeon has to suture one end of the graft vessel to the coronary artery and the other end of the graft vessel to a blood supplying vein or artery. The suturing process is a time consuming and difficult procedure requiring a high level of surgical skill. In order to perform the suturing of the graft to the coronary artery and the blood supplying artery the surgeon must have relatively unobstructed access to the anastomosis site within the patient. In the less invasive surgical approaches, some of the major coronary arteries including the ascending aorta cannot be easily reached by the surgeon because of their location. This makes suturing either difficult or impossible for some coronary artery sites. In addition, some target vessels, such as heavily calcified coronary vessels, vessels having very small diameter, and previously bypassed vessels may make the suturing process difficult or impossible.
Accordingly, it would be desirable to provide a sutureless vascular anastomosis device which easily connects a graft to a target vessel. It would also be desirable to provide a sutureless anastomosis device which is formed of one piece and is secured to the target vessel in a single step.
A superelastic or pseudoelastic one piece anastomosis device according to the present invention connects a graft vessel to a target vessel. The anastomosis device deforms from an insertion configuration to a tissue holding configuration due to the superelastic or pseudoelastic properties of the material.
In accordance with one aspect of the present invention, a one piece anastomosis device for connecting a graft vessel to a target vessel includes a device body formed of a superelastic or pseudoelastic material. The device body has an insertion configuration and a tissue holding configuration in which the body has an inner flange and an outer flange. At least one of the inner and outer flanges is radially constrained in the insertion configuration for insertion into the target vessel. When the device body is released it self deforms to the tissue holding configuration.
In accordance with another aspect of the present invention, a tube deployed anastomosis system for connecting a graft vessel to a target vessel includes a deployment tube and an anastomosis device formed of a superelastic or pseudoelastic material. The device has an insertion configuration and a tissue holding configuration in which the device has an inner flange and an outer flange. The inner and outer flanges are radially constrained in the deployment tube in the insertion configuration for insertion into the target vessel and when released from the deployment tube, the device self deforms to the tissue holding configuration.
In accordance with another further aspect of the present invention, a method of deploying an anastomosis system for connecting a graft vessel to a target vessel includes the steps of: connecting a graft vessel to a one piece device formed of a superelastic or pseudoelastic material; poking a portion of the one piece device through the graft vessel; and deploying the one piece device by self deformation to a tissue holding configuration in which the device has an inner flange and an outer flange and traps the target vessel tissue between the inner flange and the outer flange.